Department of Applied Life Science, Faculty of Bioscience and Biotechnology, Sojo University

抄録

A novel phospholipase A<SUB>2</SUB> (PLA<SUB>2</SUB>) gene, named <I>PfPLA 6</I>, was found in a 6,328-bp NIS-1(5′)-a segment in the <I>Protobothrops flavoviridis</I> (Habu, Crotalinae) genome. A comparison of the aligned nucleotide sequences of Viperidae (Viperinae and Crotalinae) venom PLA<SUB>2</SUB> genes, including <I>PfPLA 6</I>, revealed the deletion of a 12-bp segment called S1EX 1 and a 55-bp segment called S2EX 1 in exon 1 and the interposition of a 219-bp segment called SINT 2 (SINE) in intron 2. A classification of Viperidae PLA<SUB>2</SUB> genes based on these structural modes indicated that the A-type genes (without SINE), including <I>PfPLA 6</I>, are evolutionarily ancestral to the B-type (Viperinae) and C-type (Crotalinae) PLA<SUB>2</SUB> genes (both with SINE). Since <I>PfPLA 6</I> is a pseudogene, an active prototype of <I>PfPLA 6</I> can be assumed to be the ancestral PLA<SUB>2</SUB> gene. Putative evolutionary processes from this A-type prototype PLA<SUB>2</SUB> gene to descendent PLA<SUB>2</SUB> genes are discussed.